[css-lists-3] Fix examples.

Author: tabatkins

css-lists-3/Overview.bs

@@ -1075,7 +1075,7 @@ The Implicit ''list-item'' Counter</h3>
 		In the following example,
 		the list is modified to count by twos:
 		<pre>
-		  ol.evens { counter-increment: list-item 2; }
+		  ol.evens > li { counter-increment: list-item 2; }
 		</pre>
 		A three-item list would be rendered as
 		<pre>
@@ -1104,7 +1104,7 @@ The Implicit ''list-item'' Counter</h3>
 		that hooks into the ''counter-increment/list-item'' counter,
 		and thus respects any numbering changes inflicted through HTML:
 		<pre>
-		  ol::marker { content: counters(list-item,'.') '.'; }
+		  ol > li::marker { content: counters(list-item,'.') '.'; }
 		</pre>
 		Nested lists using this rule would be rendered like
 		<pre>